The proposed study is a pilot study for a multi-center study designed by the Asthma Clinical Research Network (a collaborative network of 6 research centers supported by the National Heart, Lung and Blood Institute) to determine the dose-systemic effect relationship of inhaled corticosteroids in adult subjects with mild asthma. The study design involves doubling the daily dose of different inhaled corticosteroid preparations at weekly intervals; the principle effect measured will be the overnight secretion of cortisol as measured in serum samples obtained hourly between 11PM and 7AM. Other outcomes measured will be overnight urinary cortisol, the rise in cortisol provoked by a low-dose ACTH stimulation test performed at 7AM, serum osteocalcin and urinary N- Teleopeptide. The protocl involves 7 visits, five of them requiring an overnight stay in the GCRC for overnight urine collection and hourly blood sampling. In the pilot study of 5 subjects (at UCSF; 5 subjects will also be studied at the other paritcipating sites), we proposed to administer placebo aerosol over the week prior to the first overnight stay, and then to give progressively increasing daily doses of beclomethasone (starting dose 168 ug/d) or fluticasone (starting dose 88 ug/d), increasing to final doses of 1344 ug/d and 704 ug/d, respectively. From the results of this pilot study, we plan to calculate the sample size necessary to define the dose-systemic-effect relationship for the five different inhaled corticosteroid preparations now available in the U.S.